1. Field of the Invention
The present invention relates to a multilayer ceramic capacitor and a mounting board having the multilayer ceramic capacitor mounted thereon.
2. Description of the Related Art
In general, a multilayer ceramic capacitor, a multilayer chip electronic component, is a chip type condenser mounted on circuit boards of various electronic products such as image display devices, including liquid crystal displays (LCDs), plasma display panels (PDPs), and the like, computers, smartphones, mobile phones, and the like, and serving to charge and discharge electricity.
This multilayer ceramic capacitor (MLCC) may be used as a component in various electronic products due to advantages of a relatively small size, high capacitance, and ease of mounting.
The multilayer ceramic capacitor may have a structure in which a plurality of dielectric layers and a plurality of internal electrodes having different polarities, interposed between the dielectric layers, are laminated alternately with each other.
Since the dielectric layers have piezoelectric properties and electrostrictive properties, a piezoelectric phenomenon may occur and thus cause vibrations among the internal electrodes when alternating current (AC) or direct current (DC) voltage is applied to the multilayer ceramic capacitor.
Such vibrations may be transferred to a printed circuit board on which the multilayer ceramic capacitor is mounted, through a solder connection of the multilayer ceramic capacitor, and the entire printed circuit board may become an acoustic reflection surface transmitting the vibrating sound as noise.
The vibrating sound may correspond to sound within an audible frequency range of 20 to 20000 Hz, and this vibrating sound, potentially providing unpleasant feeling to listeners is known as acoustic noise.
In order to reduce acoustic noise, products in which a lower cover layer of a multilayer ceramic capacitor included therein is thickened have been studied.
In addition, the multilayer ceramic capacitor with a thickened lower cover layer may be mounted on a printed circuit board in a horizontal mounting scheme while the thickened lower cover layer is located below, favorably reducing acoustic noise.
Meanwhile, in the case of the products in which a lower cover layer of a multilayer ceramic capacitor is thickened in order to reduce an amount of generated acoustic noise, the number of laminations is increased or the dielectric layer is thinned in order to implement a high degree of capacitance, but these may cause faults such as cracks or delamination during a sintering process.